PTR Lookup

Free PTR lookup: reverse DNS for any IP address

Enter an IPv4 or IPv6 address to see which hostname PTR records return from major public resolvers.

When you need PTR lookup

Mail server validation

Many MTAs expect sending IPs to have matching forward and reverse DNS.

FCrDNS checks

Confirm PTR hostnames resolve back to the original IP with our FCrDNS tools.

Incident triage

Turn a firewall IP into a hostname hint before deeper WHOIS work.

Infrastructure audits

Bulk-validate PTR coverage across a netblock during provider migrations.

Note: the interactive tool lives at /tools/reverse-lookup. This page targets the "PTR lookup" search phrase.